Nanga Parbat Revisited: Evolution and Dynamics of Sociohydrological Interactions in the Northwestern Himalaya

Regular availability of glacier and snow meltwater is essential for irrigated crop cultivation in the northwestern Himalaya. Based on a case study from the Nanga Parbat region in Gilgit-Baltistan, Pakistan, general patterns and site-specific particularities of irrigation networks in semiarid high mountain regions are conceptualized as continuously evolving sociohydrological interactions. These interactions are shaped by an interplay of glacio-fluvial runoff, water distribution, socioeconomic setting, institutional arrangements, external development interventions, and historical trajectories. Building on the paradigm of sociohydrology that changes in water availability coevolve with socioeconomic and land use transitions, this article explores glacier fluctuations and associated developments in meltwater-dependent crop cultivation in the Rupal Valley. The evolution of irrigation networks is analyzed using multitemporal high-resolution satellite imagery, repeat photography, and primary socioeconomic data collected in successive field surveys. Changes are historically contextualized with the help of archival material such as colonial reports and cadastral maps. This integrative study discovered the extension of cultivated areas, an increase in individual field numbers, and a reduction in average field size against the background of population increase and glacier retreat. Despite socioeconomic and environmental changes, the strong coupling of the human–water system remains intact, demonstrating a high degree of persistence of sociohydrological features over time. Adaptive strategies, however, often fail in the face of unpredictable natural processes.